The adrenal glands of humans are subdivided into two regions, the adrenal medulla and the adrenal cortex. The latter secretes a number of hormones that are known as corticoids and belong to one of two categories, Glucocorticoids (mainly hydrocortisone or cortisol) primarily act on the carbohydrate and glucose metabolism, and secondarily, they can delay wound healing by interfering with the inflammatory processes, and the formation of fibrous tissue. The second category, the mineral corticoids, are primarily involved in sodium retention and potassium excretion. The most important and effective mineral corticoid is aldosterone.
The biosynthesis of glucocorticoids is controlled, inter alia, by adrenocorticotropic hormone (ACTH). Steroid 11β, hydroxylase (CYP11B1) is the key enzyme of the biosynthesis of glucocorticoids in humans. In all diseases accompanied by increased cortisol production, this enzyme could play a crucial role. Such clinical pictures include hypercortisolism, especially Cushing's syndrome, and a more specific form of diabetes mellitus that is characterized by an extreme morning rise of the cortisol plasma level.
In the case of Cushing's syndrome, the therapy is usually selected as a function of the cause of the disease. A distinction is made between hypothalamic-pituitary and adrenally caused Cushing's syndrome, which develops due to corticoid-producing tumors of the adrenal cortex.
For the therapy of hypothalamic-pituitary Cushing's syndrome, neuromodulatory substances, such as bromocriptine, cyproheptadine, somastatin or valproic acid, are usually employed; they are supposed to reduce cortisol production through their influence on ACTH release. This therapy proved little effective in the past.
In adrenal Cushing's syndrome, especially if a surgical removal of the primary tumor is not possible, a therapy with inhibitors of steroid biosynthesis is performed. The substances employed include the non-specific CYP enzyme inhibitors aminoglutethimide, metyrapone, ketoconazole and mitotane, which are often employed in the form of a combination therapy. However, the effect on steroidogenesis is based on an attack on CYP11A1, desmolase, in the case of amino-glutethimide, or on the inhibition of CYP17 in the case of ketoconazole. The other compounds mentioned also act non-specifically. Both the combination of several non-selective inhibitors of the steroidogenic CYP enzymes and the high doses that must be employed are objectionable therapeutically. This is of importance mainly in view of the fact that the therapy must be performed for a lifetime and is associated with severe side effects due to the lack of selectivity of the compounds mentioned (Nieman, L. K., Pituitary 5; 77-82 (2002)). In this case, an approach to a solution is the therapy with highly selective inhibitors of the key enzyme of glucocorticoid biosynthesis, CYP11B1. In this case too, selectivity of the compounds is desired lest side effects should occur, especially on androgen production in males (ketoconazole) or on the biosynthesis of mineral corticoids, as described in the past.
Increased cortisol levels are also associated with neurodegenerative diseases. The decline of memory and learning ability upon exposure to increased concentrations of both exogenous and endogenous glucocorticoids (cortisol) has been described (Heffelfinger et al., Dev. Psychopathol. 13: 491-513 (2001)).
In a special form of stress-related diabetes mellitus, a rapid morning rise of the plasma cortisol level occurs. This so-called dawn phenomenon frequently occurs in type 2 diabetics and is characterized by reduced glucose tolerance and a reduction of insulin sensitivity in the early morning hours. The dawn phenomenon complicates diabetic control, so that insulin pump therapy often becomes necessary. With respect to the pathologically altered circadiane rhythm of glucose metabolism in type 2 diabetes, there are results that clearly indicate that this disorder is due to an increase of night cortisol concentrations (Bolli et al., N. Engl. J. Med. 310 (1984) 746-750; Shapiro et al., J. Clin. Endocrinol. Metab. 72 (1991) 444-454; Schultes and Fehm, Der Internist 9 (2004) 983-993).
Further, in diabetes mellitus, increased cortisol levels are attributed to the development of insulin resistance and impairment of glucose tolerance (Phillips et al., J. Clin. Endocrinol. Metab. 83: 757-760 (1998)). The liver plays a central role in the control of glucose equilibrium and in the development of glucose intolerance and type 2 diabetes mellitus. Under physiological conditions, 25% of the glucose supply is accounted for by gluconeogenesis (synthesis of glucose from lactate, pyruvate, glycerol and amino acids) in the liver, while 90% of the glucose are generated in the liver by gluconeogenesis in diabetes mellitus type 2 patients. Glucocorticoids antagonize the action of insulin, regulate hepatic glucose release and result in an increase of the blood glucose levels in diabetes mellitus. Their action consists in controlling the transcription of several genes involved in the regulation of hepatic gluconeogenesis (DeFronzo et al., Diabetes Rev. 5 (1997) 177-269).
The tissue-specific response is regulated by glucocorticoid receptor and the intracellular synthesis of active glucocorticoids by 11beta-hydroxysteroid dehydrogenase type 1 (11β-HSD-1). 11β-HSD-1 catalyzes the production of cortisol from cortisone in the liver and in adipocytes and the pancreatic beta cells and thus controls the effect of glucocorticoids in the respective target tissues (Stewart and Krozowski, Vitam. Horm, 57: 249-324 (1999)).
Currently, the application of inhibitors of 11β-HSD-1 is tested for regulating the blood glucose level. In this connection, Alberts et al. report that the selective 11β-HSD-1 inhibitor BVT.2733 resulted in the reduction of both blood glucose levels and insulin levels in hyperglycemic and hyperinsulinic mice (Alberts et al., Diabetologica 45 (2002) 1528-1532). In this case too, selective CYP11B1 inhibitors could reduce the increased cortisol release that results in a rise of the blood glucose levels and reduction of insulin sensitivity.
The application of inhibitors of 11β-HSD-1 for the regulation of blood glucose level is described, for example, in EP 1 461 333. The indications for 11-HSD-1 inhibitors also apply, mutatis mutandis, for the application of CYP11B1 inhibitors. In this case too, the inhibition of glucocorticoid biosynthesis by the direct and selective inhibition of the key enzyme CYP11B1 could be a therapeutic alternative.
Aldosterone secretion is regulated by a number of signals: the plasma concentrations of sodium and potassium and the renin-angiotensin-aldosterone system (RAAS), which proceeds through several steps. In this system, in response to a low blood pressure, the kidneys secrete renin that releases angiotensin I from a precursor peptide. Angiotensin I is in turn cleaved into angiotensin II, which comprises 8 amino acids and is a potent vasoconstrictor. In addition, it acts as a hormone for stimulating the release of aldosterone (Weber, K. T. & Brilla, C. G., Circulation 83: 1849-1865 (1991)).
The key enzyme of mineral corticoid biosynthesis, CYP11B2 (aldosterone synthase), a mitochondrial cytochrome P450 enzyme, catalyzes the production of the most potent mineral corticoid, aldosterone, from its steroidal substrate 11-deoxycorticosterone (Kawamoto, T. et al., Proc. Natl. Acad. Sci. USA 89: 1458-1462 (1992)). Excessive plasma aldosterone concentrations are related to clinical pictures such as congestive heart failure, myocardial fibrosis, ventricular arrhythmia, stimulation of cardiac fibroblasts, cardiac hypertrophy, reduced renal perfusion and hypertension, and they are also involved in the progression of these diseases (Brilia, C. G., Herz 25: 299-306 (2000)). Especially in patients suffering from chronic heart failure or reduced renal perfusion of kidney artery stenoses, a pathophysiological activation of the renin-angiotensin system (RAAS) occurs in contrast to its physiological action (Young, M Funder, J. W., Trends Endocrinol. Metab. 11: 224-226 (2000)). Angiotensin II-mediated vasoconstriction and water and sodium restriction, which occur due to the increased aldosterone levels, result in an additional extra load of the myocardium, which is already subject to primary insufficiency. In a kind of vicious circle, this results in a further reduction of renal perfusion and increased renin secretion. In addition, the increased plasma aldosterone and angiotensin II levels as well as aldosterone secreted locally in the heart induce fibrotic structural changes of the myocardium, which results in the formation of myocardial fibrosis, which leads to a further reduction of heart performance (Brilla, C. G., Cardiovasc. Res. 47: 1-3 (2000); Lijnen, P. & Petrov, V., J. Mol. Cell. Cardiol. 32: 865-879 (2000)).
Fibrotic structural changes are characterized by the formation of tissue that is characterized by an abnormally high amount of fibrotic material (mainly collagen strands). In some situations, such as wound healing, such fibroses are useful, but may also be deleterious, such as when adversely affecting the function of inner organs, inter alia. In myocardial fibrosis, the heart muscle is nerved by fibrotic strands that render the muscle stiff and inflexible and thereby impair its function.
Since the mortality is 10-20% even for patients with only a slight cardiac failure, it is absolutely necessary to interfere by using a suitable drug therapy. Despite long-term therapy with digitalis glycosides, diuretics, ACE inhibitors or AT-II antagonists, the plasma aldosterone levels remain elevated in the patients, and the drug treatment has no effect with respect to the fibrotic structural changes.
Mineral corticoid antagonists, especially aldosterone-blocking drugs, are already the subject of numerous patents. Thus, the steroidal mineral corticoid antagonist spironolactone (17-hydroxy-7-alpha-mercapto-3-oxo-17-α-pregn-4-ene-21-carboxylic acid γ-lactone acetate; Aldactone®) blocks aldosterone receptors in competition with aldosterone and thus prevents the receptor-mediated action of aldosterone. US 2002/0013303, U.S. Pat. No. 6,150,347 and U.S. Pat. No. 6,608,047 describe the dosing of spironolactone for the therapy or prophylaxis of cardiovascular diseases and myocardial fibrosis while retaining the patient's normal electrolyte and water metabolism.
The “Randomized Aldactone Evaluation Study (RALES)” (Pitt, B. et al., New Engl. J. Med. 341: 709-717 (1999)) impressively showed that the administration of the aldosterone receptor antagonist spironolactone (Aldactone®) in addition to the basic therapy with ACE inhibitors and loop diuretics could significantly improve the survival rate of patients with severe heart failure, because the action of aldosterone was sufficiently inhibited (Kulbertus, H., Rev. Med. Liege 54: 770-772 (1999)). However, the application of spironolactone was accompanied by severe side effects, such as gynecomasty, dysmenorrhoea and breast pain, which are due to the steroidal structure of the substance and the resulting interactions with other steroid receptors (Pitt, B. et al., New Eng, J. Med. 341: 709-717 (1999); MacFadyen, R. J. et al., Cardiovasc. Res. 35: 30-34 (1997); Soberman, J. E. & Weber, K. T., Curr. Hypertens. Rep. 2: 451-456 (2000)).
Mespirenone (15,16-methylene-17-spirolactone) and its derivatives were considered promising alternatives for spironolactone, since they exhibit only a low percentage of the anti-androgenic effect of spironolactone (Losert, W. et al., Drug Res. 36: 1583-1600 (1986); Nickisch, K. et al., 3 Med Chem 30(8); 1403-1409 (1987); Nickisch, K. et al., J. Med. Chem. 34: 2464-2468 (1991); Agarwal, M. K., Lazar, G., Renal Physiol. Biochem. 14: 217-223 (1991)). Mespirenone blocks aldosterone biosynthesis as part of a complete inhibition of mineral corticoid biosynthesis (Weindel, K. et al., Arzneimittelforschung 41(9): 946-949 (1991)). However, like spironolactone, mespirenone inhibits aldosterone biosynthesis only in very high concentrations.
WO 01/34132 describes methods for the treatment, prophylaxis or blocking of pathogenic change resulting from vascular injury (restenoses) in mammals by administering an aldosterone antagonist, namely eplerenone (an aldosterone receptor antagonist) or related structures which are in part epoxysteroidal and all of which can be derived from 20-spiroxanes.
WO 96/40255, US 2002/0123485, US 2003/0220312 and US 2003/0220310 describe therapeutic methods for treating cardiovascular diseases, myocardial fibrosis or cardiac hypertrophy by using a combination therapy of an angiotensin II antagonist and an epoxy-steroidal aldosterone receptor antagonist, such as eplerone or epoxymexrenone.
The recently published study EPHESUS (“Eplerenone's Heart Failure Efficacy and Survival Study”, 2003) could support the RALES results. Administered as a supplement to the basic therapy, the first selective steroidal mineral corticoid receptor antagonist eplerone (Inspra®) clearly reduces morbidity and mortality in patients with acute myocardial infarction and the occurrence of complications, for example, reduced left-ventricular ejection fraction and heart failure (Pitt., B. et al., N. Eng. J. Med. 348: 1390-1382 (2003)).
RALES and EPHESUS clearly demonstrated that aldosterone antagonists are a therapy option that is not to be underestimated. However, their side effect profile urges a demand for substances which are distinguished from spironolactone in structure and mechanism of action. A promising alternative are non-steroidal inhibitors of mineral corticois biosynthesis, because it is better to reduce the pathologically increased aldosterone concentration than just to block the receptors. In this connection, CYP11B2 as a key enzyme offers itself as a target for specific inhibitors and has already been proposed as a target for specific inhibitors in earlier studies (Hartmann, R. et al., Eur. J. Med. Chem. 38: 363-366 (2003); Ehmer, P. et al., J. Steroid Blochem. Mol. Biol. 81: 173-179 (2002)). Thus, the excessive generalized release of aldosterone and especially cardiac aldosterone production can be reduced by the selective inhibition of its biosynthesis, which in turn reduces structural changes in the myocardium.
Selective aldosterone synthase inhibitors could also be a promising class of substances that promote the healing of the impaired myocardial tissue with reduced scar formation after a myocardial infarction and thus reduce the occurrence of severe complications.
WO 01/76574 describes a medicament which comprises an inhibitor of aldosterone production or one of its pharmaceutically acceptable salts, optionally in combination with other active substances. WO 01/76574 relates to the use of, at the time, commercially available non-steroidal inhibitors of aldosterone production, especially the (+)-enantiomer of fadrozole, a 4-(5,6,7,8-tetrahydroimidazo-[1,5-a]pyridine-5-yl)benzonitrile, and its synergistic action with angiotensin II receptor antagonists.
Anastrozole (Arimidex®) and exemestane (Coromasin®) are further non-steroidal aromatase inhibitors. Their field of application is the treatment of breast cancer by inhibiting the aromatase that converts androstendione and testosterone to estrogen.
Human steroid 11β-hydroxylase CYP11B1 shows a homology of more than 93% with human CYP11B2 (Kawamoto, T. et al., Proc. Natl. Acad. Sci. USA 89: 1458-1462 (1992); Taymans, S. E. et al., J. Clin. Endocrinol. Metab. 83: 1033-1036 (1998)). Despite the high structural and functional similarity between these two enzymes, strong inhibitors of aldosterone synthase must not influence the steroid 11β-hydroxylase and therefore must be tested for selectivity. In addition, non-steroidal inhibitors of aldosterone synthase should be preferably applicable as therapeutic agents since less side effects on the endocrine system are to be expected. This has been pointed out in earlier studies, as has the fact that the development of selective CYP11B2 inhibitors that do not influence CYP11B1 is complicated by the high similarity between the two enzymes (Ehmer, P. et al., J. Steroid Biochem. Mol. Biol. 81: 173-179 (2002); Hartmann, R. et al., Eur. J. Med. Chem. 38: 363-366 (2003)).
The inhibitors should also affect other P450 (CYP) enzymes as little as possible. The only active substance known to date which influences the corticoid synthesis in humans is the aromatase (estrogen synthase, CYP19) inhibitor fadrozole, which is employed in breast cancer therapy. It may also influence aldosterone and cortisone levels, but only when ten times the therapeutic dose is administered (Demers, L. M. et al., J. Clin. Endocrinol. Metabol. 70: 1162-1166 (1990)).
For inhibitors of the human aldosterone synthase CYP11B2, a test system for screening chemical compounds with Schizosaccharomyces pombe cells that stably express human CYP112 and for subsequently testing the selectivity with V79MZ cells that stably express either CYP11B2 or CYP11B has been developed (Ehmer, P. et al., 3, Steroid Biochem, Mol. Biol. 81: 173-179 (2002)). By means of the S. pombe system, 10 substances were tested in an exemplary manner, of which one was identified as a potent and selective non-steroidal inhibitor of human CYP11B2 (and strong aromatase inhibitor) and four others were identified as non-selective inhibitors, but which were stronger towards CYP11B1, by means of the V79MZ system (A: CYP11B2 inhibitor; B-D: non-selective CYP11B1 inhibitors):

However, this publication was focused on the provision of an effective test system for the screening for selective CYP11B2 inhibitors, and except the quite general reference to the aromatic N atom and the three structures shown above, it gives very few indications of what classes of substances could be particularly effective ultimately. Further, it may be noted that most of the structures presented in this publication were strong CYP11B1 inhibitors and therefore should not be taken into account for immediate use as selective CYP11B2 inhibitors.
The screening of a P450 inhibitor library of more than 100 substances for inhibitors of bovine aldosterone synthase (CYP18, CYP11B) (in part published in Hartmann, R. W. et al., Arch. Pharm. Pharm. Med. 339, 251-61 (1996)) by means of the test system presented by Ehmer et al. (Ehmer, P. et al., 1. Steroid Biochem. Mol. Biol. 81: 173-179 (2002)) yielded a high number of compounds that have an inhibitors effect on CYP11B2 (Hartmann, R. et al., Eur. J. Med. Chem. 38; 363-366 (2003)). In the scope of the cited study, these substances were also tested for oral availability and further for in vitro inhibition of human CYP11B2 stably expressed in yeast and, if these tests showed a strong inhibition of CYP11B2, in V79MZ cells. Comparisons with the inhibition of other CYPs, including CYP11B1, expressed in V79MZ cells were also made in order to establish the selectivity of the test substances. By structural variation, finally, CYP11B2 inhibitors that showed IC50 values in the low nanomolar range were found, namely cyclopropatetrahydronaphthalene derivatives and arylmethyl-substituted indanes. It has been established that the CYP11B inhibition is strongly influenced by the substituent at the benzene ring and by the heteroaryl residue. Compounds E and F were found as promising lead structures:

The above mentioned scientific publications indicate that the presence of an aromatic nitrogen atom is essential to the complexing of the iron atom in the target enzyme (Ehmer, P. et al., J. Steroid Biochem. Mol. Biol. 81: 173-179 (2002); Hartmann, R. et al., Eur. J. Med. Chem. 38; 363-366 (2003)). In addition, this N atom must be unsubstituted and sterically accessible (Ehmer, P. et al., J. Steroid Biochem. Mol. Biol. 81: 173-179 (2002)).
Only a few heteroaryl-substituted dihydronaphthalenes were tested for their activity as inhibitors of non-specific bovine CYP11B already in the preliminaries to the invention presented here (Hartmann, R. W. et al., Arch. Pharm. Pharm. Med. Chem. 329: 251-261 (1996)):

Their effect on CYP17 and CYP19 is also described in this publication. However, they proved to be too non-specific to be considered as therapeutic agents for the selective inhibition of CYP11B2. In addition, the bovine enzyme is not optimal for evaluating the therapeutic usefulness of compounds for the inhibition of human CYP11B enzymes, since the homology between this bovine enzymes and the human enzymes is not high (75%) (Mornet, E. et al., J. Biol, Chem. 264, 20961-20967 (1989)).
Further, the effect of the following compound on CYP17, CYP19 and TxA2 (thromboxane A2 synthase) has been described, but an inhibitory effect on CYP11B has not been mentioned (Jacobs, C. et al., J. Med. Chem. 43: 1841-1851 (2000)):

Further 1-imidazolyl- and 4-pyridyl-substituted naphthalenes, dihydronaphthalenes, quinolines and their oxa analogues of formula
are described as TxA2 inhibitors (Cozzi, P. et al., Eur. J. Med. Chem. 26: 423-433 (1991)).
Also,
has already been mentioned as an inhibitor of CYP17 (Bencze, W. L. and Barsky, L. I., J. Med. Pharm. Chem. 5: 1298-1306 (1962) and U.S. Pat. No. 3,165,525).
Further,
has been proposed as a tool for the diagnosis of primary and secondary aldesteronism and diabetes mellitus as an alternative for metyrapone (Johnson, A. L. et al., J. Med. Chem. 12(5): 1024-1028 (1969)).
Some pyridine-substituted quinolines are thought to have a spasmolytic effect (Hey, D. H. und Williams, J. M., J. Chem. Soc. 1678-83 (1950)).
U.S. Pat. No. 3,098,077 discloses 2-pyridylindenes and their use for inhibiting hyperadrenocortfcism.
All inhibitors of aldosterone or glucocorticoid production known to date have substantial drawbacks: Etomidate and metyrapone inhibit glucocorticoid production more strongly than they inhibit aldosterone production. Etomidate is a strong narcotic, and metyrapone is a relatively non-selective CYP inhibitor which is therefore employed only as a diagnostic agent. Fadrozole has been described to inhibit aldosterone production more strongly than it inhibits glucocorticoid production (Bhatnagar, A. S. et al., J. Steroid Biochem. Mol. Biol. 37: 1021-1027 (1990); Hausler, A. et al., J. Steroid Biochem. 34: 567-570 (1989); Dowsett, M. et al., Clin. Endocrinol. (Oxf.) 32: 623-634 (1990); Santen, R. J. et al., J. Clin. Endocrinol. Metabol. 73: 99-106 (1991); Demers, L. M. et al., J. Clin. Endocrinol. Metabol. 70; 1162-1166 (1990)). This substance cannot be considered for application as an inhibitor of aldosterone or glucocorticoid production either, because it is a very strong aromatase inhibitor and therefore interferes with the production of sexual hormones with high potency. In the light of the above mentioned prior art, there has been a need for potent and selective inhibitors of the 11β-hydrolase CYP11B1 and the aldosterone synthase CYP11B2.
3-Pyridyl-substituted quinolines and quinoxalines were prepared already by a Fe(salen)Cl-catalyzed cross-coupling reaction of a correspondingly chlorinated heteroaryl with a pyridyl Grignard compound (Furstner, A. et al., JACS 124: 13866-13863 (2002)).
The 3-pyridyl Grignard compound also reacts with ethyl-2-quinolinyl sulfoxide to give 2-pyridine-3-ylquinoline 20 (Furukawa, N. et al., Tet. Lett. 28(47): 5845-8 (1987)). Another synthesis method for this compound is the treatment of o-aminobenzaldehyde with 3-pyridylmethylketone (Hey, D. H. and Williams, J. M., J. Chem. Soc. 1678-83 (1950)).
3-Pyridine-3-ylquinoline 19 can be prepared by a palladium-catalyzed cross-coupling reaction of tri(quinolinyl)magnesate with 6-bromopyridine (Dumouchel, S. et al., Tetrahedron 59: 8629-8640 (2003)). 2-Pyridine-3-ylquinoxaline 21 is obtainable by reacting o-phenylenediamine with brominated 3-pyridylmethylketone (Sarodnick G. and Kempter G., Pharmazie 40(6); 384-7 (1985)).
All mentioned cross-coupling reactions with iron or palladium complexes have drawbacks: For preparing the iron complex, an additional synthetic step becomes necessary, and the coupling of arylmagnesates requires the expensive ligand dppf (1,1′-bis(diphenylphosphino)ferrocene). In addition, the safe handling of the reagents is difficult, and a dry atmosphere and low temperatures are indispensable.
The mentioned reaction of 3-pyridylmethylketone with o-aminobenzaldehyde or o-phenylenediamine results in low yields (20% maximum). Although the synthesis of 4-(6-methoxy-2-naphthyl)pyridine 31 has been described (Kelley, C. J., J. Het. Chem. 38(1): 11-23 (2001)), it involves quite a lot of individual steps.
Therefore, there has also been a need for a simple synthesis method for heteroaryl substituted naphthalenes, 3,4-dihydroxynaphthalenes and indanes, which can be applied to a broad range of heteroaryls.